Germany's 9-Euro-Ticket (2022) — A Three-Month National Fare Experiment With Measured but Modest Car Substitution

Between June and August 2022 Germany offered a €9-a-month ticket valid on local and regional public transport nationwide, as part of an inflation-relief package. It functioned as a large natural experiment on fare levels.
The most rigorous available evidence is a panel by TUM, LMU and partners (Loder et al., arXiv 2306.08297, 2023): 2,261 initial participants centred on the Munich region, 756 with smartphone tracking data and 1,402 survey respondents. Public transport's modal share rose at the expense of the car by roughly 5% in travel distance and 7% in trip frequency. The authors conclude that cheap public transport alone does not sufficiently encourage sustainable travel and that other policy tools are needed.
Other estimates differ: the transport association VDV, using a survey of about 100,000 respondents, reported that about 10% of ticket trips would otherwise have been made by car, while an ifo-led study reported car traffic down by 4–5% with a minimal decline at weekday commuting peaks. The spread between industry and academic estimates is itself a lesson about method.
The experiment fed into the permanent Deutschlandticket (launched 2023 at a higher price). Its value for other cities is as a documented, time-limited fare experiment with mixed results rather than as proof that low fares alone shift travel.

Read the full analysis: https://vision-mobility.de/en/news/ifo-9-euro-ticket-has-little-climate-effect-brings-few-switchers-and-more-delays-335038.html